/**
 * AKSRT Effects — count-up / countdown / marquee / 3D tilt / FPS detection
 *
 * 全部渐进增强，尊重 prefers-reduced-motion。
 *
 * @package AKSRT
 */

(function () {
  'use strict';

  var reducedMotion = window.matchMedia && window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  var countUpObserver = null;
  var countdownElements = [];
  var countdownTimer = null;
  var fpsDetectionStarted = false;

  function scopeFor(root) {
    return root && root.querySelectorAll ? root : document;
  }

  function eachMatch(root, selector, callback) {
    var scope = scopeFor(root);
    if (scope.nodeType === 1 && scope.matches(selector)) callback(scope);
    scope.querySelectorAll(selector).forEach(callback);
  }

  function animateCountUp(el) {
    if (el.dataset.aksrtCountupBound === '1') return;
    el.dataset.aksrtCountupBound = '1';
    countUpObserver.observe(el);
  }

  function initCountUp(root) {
    if (reducedMotion || !('IntersectionObserver' in window)) return;
    if (!countUpObserver) {
      countUpObserver = new IntersectionObserver(function (entries) {
        entries.forEach(function (entry) {
          if (!entry.isIntersecting) return;
          var el = entry.target;
          countUpObserver.unobserve(el);
          var target = parseFloat(el.dataset.target || '0');
          var duration = parseInt(el.dataset.duration || '2000', 10);
          var decimals = (el.dataset.decimals || '0|').split('|');
          var prefix = decimals[1] || '';
          var dec = parseInt(decimals[0], 10) || 0;
          var startTime = null;

          function step(timestamp) {
            if (!startTime) startTime = timestamp;
            var progress = Math.min((timestamp - startTime) / duration, 1);
            var current = target * (1 - Math.pow(1 - progress, 3));
            el.textContent = prefix + current.toFixed(dec).replace(/\B(?=(\d{3})+(?!\d))/g, ',');
            if (progress < 1) requestAnimationFrame(step);
            else el.textContent = prefix + target.toFixed(dec).replace(/\B(?=(\d{3})+(?!\d))/g, ',');
          }

          requestAnimationFrame(step);
        });
      }, { threshold: 0.3 });
    }
    eachMatch(root, '[data-aksrt-countup]', animateCountUp);
  }

  function pad(n) { return n < 10 ? '0' + n : '' + n; }

  function updateCountdowns() {
    var now = Date.now();
    countdownElements = countdownElements.filter(function (el) { return document.documentElement.contains(el); });
    countdownElements.forEach(function (el) {
      var end = new Date(el.dataset.end).getTime();
      var diff = end - now;
      if (diff <= 0) {
        el.textContent = el.dataset.expired || '已结束';
        return;
      }
      var d = Math.floor(diff / 86400000);
      var h = Math.floor((diff % 86400000) / 3600000);
      var m = Math.floor((diff % 3600000) / 60000);
      var s = Math.floor((diff % 60000) / 1000);
      var format = el.dataset.format || 'dhms';
      if (format === 'dhms') el.textContent = (d > 0 ? d + '天 ' : '') + pad(h) + ':' + pad(m) + ':' + pad(s);
      else if (format === 'hms') el.textContent = pad(h + d * 24) + ':' + pad(m) + ':' + pad(s);
      else el.textContent = (d > 0 ? d + '天 ' : '') + pad(h) + '时' + pad(m) + '分' + pad(s) + '秒';
    });
  }

  function initCountdown(root) {
    eachMatch(root, '[data-aksrt-countdown]', function (el) {
      if (el.dataset.aksrtCountdownBound === '1') return;
      el.dataset.aksrtCountdownBound = '1';
      countdownElements.push(el);
    });
    updateCountdowns();
    if (!countdownTimer && countdownElements.length) countdownTimer = window.setInterval(updateCountdowns, 1000);
  }

  function initTilt(root) {
    if (reducedMotion) return;
    eachMatch(root, '[data-aksrt-tilt]', function (el) {
      if (el.dataset.tiltBound) return;
      el.dataset.tiltBound = '1';
      var maxDeg = parseFloat(el.dataset.tiltMax || '10');
      var perspective = parseFloat(el.dataset.tiltPerspective || '800');
      var scale = parseFloat(el.dataset.tiltScale || '1.03');
      var glare = el.dataset.tiltGlare === '1';
      var glareEl = null;
      if (glare) {
        glareEl = document.createElement('div');
        glareEl.style.cssText = 'position:absolute;inset:0;border-radius:inherit;pointer-events:none;background:linear-gradient(135deg,rgba(255,255,255,0) 0%,rgba(255,255,255,0.25) 100%);opacity:0;transition:opacity 0.2s;';
        el.style.position = el.style.position || 'relative';
        el.style.overflow = 'hidden';
        el.appendChild(glareEl);
      }
      el.addEventListener('mousemove', function (e) {
        var rect = el.getBoundingClientRect();
        var x = (e.clientX - rect.left) / rect.width;
        var y = (e.clientY - rect.top) / rect.height;
        el.style.transform = 'perspective(' + perspective + 'px) rotateX(' + ((0.5 - y) * maxDeg) + 'deg) rotateY(' + ((x - 0.5) * maxDeg) + 'deg) scale3d(' + scale + ',' + scale + ',' + scale + ')';
        if (glareEl) glareEl.style.opacity = '1';
      });
      el.addEventListener('mouseleave', function () {
        el.style.transform = 'perspective(' + perspective + 'px) rotateX(0deg) rotateY(0deg) scale3d(1,1,1)';
        if (glareEl) glareEl.style.opacity = '0';
      });
    });
  }

  function initFpsDetection(root, reason) {
    if (fpsDetectionStarted || !('requestAnimationFrame' in window)) return;
    fpsDetectionStarted = true;
    var frames = 0;
    var startTime = performance.now();
    function countFrames() {
      frames++;
      var elapsed = performance.now() - startTime;
      if (elapsed >= 1000) {
        if (Math.round(frames * 1000 / elapsed) < 24 && document.body) document.body.classList.add('fps-accelerat');
        return;
      }
      requestAnimationFrame(countFrames);
    }
    requestAnimationFrame(countFrames);
  }

  function init(root, reason) {
    initCountUp(root);
    initCountdown(root);
    if (typeof initMarquee === 'function') initMarquee(root, reason);
    initTilt(root);
    initFpsDetection(root, reason);
  }

  window.AksrtFrontend.register('aksrt-effects', init);
})();